All ramparts flicker when a single rampart is destroyed/decays.

[Rurik]

See this replay:

https://screeps.com/a/#!/history/shard2/W25N13?t=4244395

Thanks to my terrible rampart repairing code I found out that every time 1 rampart decays, all ramparts disappear before being redrawn.

Obviously this is not game breaking but it is rather distracting.